1. Field of the Invention
The present invention relates to an apparatus for cooling the cylinder head of an engine, particularly, an air cooling type internal combustion engine.
2. Description of the Prior Art
As is well known, various types of cooling methods are employed for engine, particularly, internal combustion engine in order to protect it from adversely affected state due to heat generated in combustion chambers and maintain it under the properly determined temperature condition.
The conventional cooling methods are generally classified into cooling method with the use of air flowing and cooling method with the use of water flowing.
Specifically, the air cooling method is intended to cool engine by utilizing flowing of air which passes by the surface of fins standing upright from both the cylinder block and cylinder heads of the engine.
On the other hands, the water cooling method is intended to cool engine by utilizing flowing of water through water jackets which are formed in both the cylinder block and the cylinder head.
When the air cooling method is employed for the purpose of cooling engine, there is only a necessity for forming a number of heat radiating fins on both the cylinder block and the cylinder head of the engine and this leads to an advantageous feature that the whole engine can be designed and constructed in a very simple structure. However, it has drawbacks that it is difficult to uniformly cool down the whole engine, temperature control is achieved only with much difficulties and both the cylinder block and the cylinder head are liable to be deformed thermally.
On the other hands, when the water cooling method is employed for the same purpose, every part of engine can be cooled more uniformly than the air cooling method. However, it has drawbacks that the engine is constituted by a large number of parts and components because of a necessity for arranging radiator, fan and others and moreover it is produced by way of many complicated steps (inclusive a step for producing a core) because of a necessity for forming water jackets in both the cylinder block and the water head, resulting in increased production cost.